UKidney eGFR Calculator

MDRD Equation:

\[ eGFR = 175 \times Scr^{-1.154} \times Age^{-0.203} \times (0.742 \text{ if female}) \times (1.212 \text{ if Black}) \]

Serum Creatinine (Scr):

mg/dL

Age:

years

Gender:

Race:

Estimated GFR (eGFR):

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1. What is the MDRD Equation?

The MDRD (Modification of Diet in Renal Disease) equation estimates glomerular filtration rate (GFR) from serum creatinine, age, sex, and race. It was developed to provide a more accurate assessment of kidney function in patients with chronic kidney disease.

2. How Does the Calculator Work?

The calculator uses the MDRD equation:

\[ eGFR = 175 \times Scr^{-1.154} \times Age^{-0.203} \times (0.742 \text{ if female}) \times (1.212 \text{ if Black}) \]

Where:

\( Scr \) — Serum creatinine (mg/dL)
\( Age \) — Age in years
0.742 — Female multiplier
1.212 — Black race multiplier

Explanation: The equation uses a power function relationship between creatinine and GFR, with demographic adjustments for gender and race.

3. Importance of eGFR Calculation

Details: Accurate GFR estimation is essential for diagnosing chronic kidney disease, monitoring disease progression, and adjusting medication dosages based on renal function.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, select gender and race. All values must be valid (creatinine > 0, age between 1-120).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between MDRD and CKD-EPI equations?
A: MDRD is more accurate in patients with established CKD, while CKD-EPI performs better at higher GFR levels and is less likely to misclassify individuals with normal or mildly reduced kidney function.

Q2: What are the limitations of the MDRD equation?
A: The equation may be less accurate in elderly patients, those with normal renal function, pregnant women, and individuals with extremes of body size or muscle mass.

Q3: When was the MDRD equation developed?
A: The MDRD equation was developed in 1999 and has been widely used for estimating GFR in clinical practice.

Q4: Is the MDRD equation validated for all populations?
A: While widely used, the equation may require validation or adjustment for specific ethnic groups not included in the original study population.

Q5: Can this calculator be used for children?
A: No, the MDRD equation is validated for adults only. Pediatric GFR estimation requires different equations specifically designed for children.